Optoelectronic devices based on ZnGeN2 integrated with group III-V nitrides

Abstract

Group III-V nitride semiconductors are used as light emitters for other optoelectronic devices. To provide the desired range of bandgap and band offsets in heterostructure devices, InGaN layers have to be grown. InGaN layers are difficult to grow because of lattice mismatch with GaN, and because of problems with homogeneity. Thus, ZnGeN 2 is provided as the active layer in a blue or blue-green light-emitting device. ZnGeN 2 has a bandgap in the blue region of the spectrum and is almost lattice matched to GaN, making it an ideal candidate for integration with group III-V nitrides.

What is claimed is: 
     
       1. A semiconductor structure comprising: a substrate;   at least one first nitride layer formed over the substrate;   a zinc germanium nitride (ZnGeN 2 ) layer formed over the at least one first nitride layer; and   at least one second nitride layer formed over the zinc germanium nitride layer.   
     
     
       2. The semiconductor structure according to claim 1, wherein the at least one first nitride layer and the at least one second nitride layer comprise at least one of GaN, InGaN or AlGaN. 
     
     
       3. The semiconductor structure according to claim 1, wherein the at least one first nitride layer is one of n-type doped and p-type doped, and the at least one second nitride layer is the other of n-type doped and p-type doped. 
     
     
       4. The semiconductor structure according to claim 1, wherein the at least one first nitride layer includes one nitride layer. 
     
     
       5. The semiconductor structure according to claim 1, wherein the at least one second nitride layer includes one nitride layer. 
     
     
       6. The semiconductor structure according to claim 1, wherein the semiconductor structure is an optoelectronic device. 
     
     
       7. The semiconductor structure according to claim 1, wherein the ZnGeN 2  nitride layer comprises an active layer. 
     
     
       8. The semiconductor structure according to claim 7, wherein the at least one first nitride layer and the at least one second nitride layer form confinement layers confining injected carriers into the active layer. 
     
     
       9. The semiconductor structure according to claim 1, wherein the semiconductor structure emits light in the blue region of the spectrum. 
     
     
       10. The semiconductor structure according to claim 1, wherein the semiconductor structure emits light with a wavelength within a range including 380 nm to 650 nm. 
     
     
       11. The semiconductor structure according to claim 1, further comprising electrodes providing electrical contacts to the at least one firat nitride layer and the at least one second nitride layer. 
     
     
       12. The semiconductor structure according to claim 1, wherein the zinc germanium nitride active layer has a thickness of about 1 to 50 nm. 
     
     
       13. The semiconductor structure according to claim 1, wherein the at least one first nitride layer and the at least one second nitride layer further comprise cladding layers expressed by the general formula Al x  Ga 1-x  N, where 0<x<0.4, the cladding layers having a thickness up to 2 μm. 
     
     
       14. The semiconductor structure according to claim 1, wherein the at least one first nitride layer and the at least one second nitride layer further comprise optical guiding layers expressed by the general formula In x  Ga 1-x  N, where 0<x<0.2, the optical guiding layers having a thickness of about 0.1 μm. 
     
     
       15. An image forming apparatus that forms an image on a light sensitive medium, the image forming apparatus including at least one light source that includes the semiconductor structure of claim 1. 
     
     
       16. The image forming apparatus according to claim 15, wherein the image forming apparatus includes at least one of a laser printer, a digital printer, a display device and an illumination device. 
     
     
       17. The image forming apparatus according to claim 15, wherein the at least one light source includes at least one raster output scanner and a multiple element print bar. 
     
     
       18. A data storage apparatus that stores data on a medium, the data storage apparatus including at least one light source that includes the semiconductor structure of claim 1. 
     
     
       19. The data storage device according to claim 18, wherein the data storage apparatus comprises a magneto-optical storage device. 
     
     
       20. The data storage device according to claim 18, wherein the data storage apparatus comprises any one of a CD-ROM drive and a DVD drive. 
     
     
       21. The data storage device according to claim 18, wherein the medium comprises a magneto-optical disk. 
     
     
       22. A communications apparatus that communicates information through a communications transmission medium, the communications apparatus including at least one light source that includes the semiconductor structure of claim 1. 
     
     
       23. The communications apparatus according to claim 22, wherein the communications apparatus comprises a fiber optic network. 
     
     
       24. The communications apparatus according to claim 22, wherein the at least one light source comprises at least one of a fiber optic emitter and a fiber optic repeater. 
     
     
       25. The semiconductor structure according to claim 1, wherein the at least one first nitride layer includes more than one nitride layer. 
     
     
       26. The semiconductor structure according to claim 1, wherein the at least one second nitride layer includes more than one nitride layer. 
     
     
       27. A method for forming a semiconductor structure, comprising: forming at least one first nitride layer over a substrate;   forming a zinc germanium nitride (ZnGeN 2 ) layer over the at least one first nitride layer; and   forming at least one second nitride layer over the ZnGcN, layer.   
     
     
       28. The method for forming a semiconductor structure according to claim 27, wherein the at least one first nitride layer and the at least one second nitride layer comprise at least one of GaN, InGaN and AlGaN. 
     
     
       29. The method of forming a semiconductor structure according to claim 27, wherein the at least one first nitride layer is one of n-type doped and p-type doped, and the at least one second nitride layer is the other of n-type doped and p-type doped. 
     
     
       30. The method of forming a semiconductor structure according to claim 27, wherein the ZnGeN 2  layer comprises an active layer. 
     
     
       31. The method of forming a semiconductor structure according to claim 27, comprising: forming more than one first nitride layer over the substrate; and   forming more than one second nitride layer over the ZnGeN 2  layer.